This invention relates to electroplating and particularly to high speed electroplating of a metal or alloy of metals on a moving wire. Even more particularly, this invention relates to high speed electroplating wherein uniform distribution of the electrolyte solution against the moving wire is achieved.
Initial efforts for accomplishing wire electroplating included passing the wire through a spaced series of open troughs which contained a quantity of electrolyte therein. Multiple passes were usually required in addition to providing a means for agitating the solutions in the troughs. In addition to being inefficient by manufacturing standards, the described method often resulted in produced wire having several areas of nonuniformity in the plating thicknesses.
In more recent years, the trend has been toward plating of moving wire at substantially higher rates with the result being, of course, improved productivity. Accordingly, the main emphasis in designing the plating devices or cells which accomplish this plating has been toward providing relatively high turbulence or agitation of the electrolyte solution within the device. The primary function of turbulence or agitation in such a device is to hopefully reduce the thickness of the cathode "depletion layer". This undesirable layer, usually of micron thickness, develops at the cathode solution interface and is characterized by a depletion of the required metallic ion within the electrolyte. As can be appreciated, reducing the thickness of this depletion layer is considered essential in order to achieve successful electroplating.
As can further be appreciated, successful high speed plating requires relatively high current densities per square foot of wire to assure a durable plate on the wire. To date, the best known devices capable of providing a relatively high level of electrolyte agitation have only been capable of providing current densities of approximately 500 amperes per square foot of moving wire. Such densities are considered too low for satisfactory high speed plating of wire.
It is therefore believed that a device and method capable of providing relatively high current densities in addition to high levels of agitation to the electrolyte would constitute an advancement in the art.